Home / 458.40-687.40-215

Finding the Fourth Proportional to 458.40, 687.40 and 215

Calculator

Solution

The fourth proportional to 458.40, 687.40 and 215 is: 322.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.40 : 687.40 = 215 : x
  2. Step 2: Convert to fraction form
    458.40/687.40 = 215/x
  3. Step 3: Cross multiply
    458.40x = 687.40 × 215
  4. Step 4: Simplify right side
    458.40x = 147,791
  5. Step 5: Solve for x
    x = 147,791/458.40
  6. Step 6: Final answer
    x = 322.41

Related Problems

Find fourth proportional to 229.20, 343.70 and 107.50
Half scale
Find fourth proportional to 916.80, 1,374.80 and 430
Double scale
Find fourth proportional to 459.40, 688.90 and 216
Similar ratio
Find fourth proportional to 687.60, 1,031.10 and 322.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.